Images: Ice Sheet Research

"When you fly out to the ice sheet in a helicopter, at first you see where the glacier meets the sea," said WHOI photographer Chris Linder, in a dispatch on the Polar Discovery Web site. "Next you see these deep crevasses. Then they disappear, and the ice becomes smooth. Finally, lakes appear on the ice sheet. These tiny blue jewels dot all the whiteness. And that’s where we landed. Right by one of those jewels."

WHOI glaciologist Sarah Das (orange jacket) is sometimes asked: "Do we need to worry about Greenland's ice sheet melting?" She responds this way: "It seems now unequivocally clear that our climate is warming, and it's largely induced by human activity. So in the sense that we as a society have to worry about increasing rates of sea-level rise, I think we absolutely do."

WHOI glaciologist Sarah Das (on ladder) checks a temperature sensor left for a year on an instrument tower to capture long-term, daily measurements. High platforms keep the scientists’ instruments off the Greenland ice sheet, which melts at a rate of 5 feet per year.

In fog near the edge of a glacial lake, scientists Sarah Das, Mark Behn, Ian Joughin, and Kristin Poinar (from left) listen to thunderous booms caused by a large crack forming in the bottom of a lake atop the Greenland ice sheet.